The TSA has ordered a review of airport security around the country after Friday’s shooting at LAX. But it won't be an easy task: The attack revealed glaring flaws in the way airport security is designed.

The TSA has ordered a full review of airport security around the country in the wake of Friday’s shooting at LAX, which killed one TSA agent and wounded several others. But it may not be an easy task, according to experts who say that the attack revealed some glaring flaws in the way airport security is designed.

In fact, several security sources said focusing most of the resources on protecting aircraft—the 'air side' of the terminal—has left the 'land side', or accessible portion of the airport, more vulnerable.

Issy Boim, a former El Al sky marshal and Shin Bet agent who is now a Houston-Based security consultant, points out that airport lobbies have been terror targets for decades—such as in 1985 when simultaneous attacks at airports in Rome and Vienna killed a total of 18 and wounded more than 100. LAX was the site of an earlier attack in 2002 when a gunman opened fire on an El AL counter.

"This is a very exposed place," says Boim, who first partnered with Condé Nast Traveler on a special investigation of airport security in 2006. "At many airports, the most crowded place is the check-in area." And any place you have people congregating poses a problem: At busy times at major airports "you could have 500 people there," with little apparent protection.

Indeed, ever since the TSA took over the reins from the airlines at checkpoints, a debate has simmered over whether to arm some agents. That idea was nixed, but initially after 9/11, non-TSA armed guards were prominently posted near the entrance to the checkpoint. Those guards were later phased out in favor of police patrols in open areas (whose movements wouldn’t be predictable). When I worked as a TSA screener, our instructions were simple: If a dangerous situation arose, we were to call law enforcement—period.

And while the response of the LA airport police has been commended in the wake of shooting, Boim says he was shocked at how far the gunman was able to get inside the terminal. "It's horrifying that [suspect Paul Ciancia] was able to get all the way up to the gates," by shooting his way through the checkpoint, says Boim. Arming more personnel wouldn’t necessarily be the answer, he said: "You've got too many people running around; it would be like the O.K. Corral.”

So while it may not be possible to secure the public spaces of an airport 100 percent, Boim lists some additional steps airports can take:

Install more physical barriers, including immediately after the checkpoint, to prevent someone from blasting through.

Increase boots on the ground: The TSA's own union has called for more armed guards both before and immediately after the checkpoint.

Add more eyes. Train more people, including airline personnel at check-in areas, to watch for suspicious behavior.

Use technology: Motion-detection cameras can pick up suspicious or unusual movements.

But as we reported in our story on the ten-year anniversary of TSA, there’s a bigger problem that is largely unknown to most of the flying public: The TSA doesn't have direct authority over large parts of the airport beyond the actual checkpoint. A patchwork of state and local agencies are in charge of most of the land side, and the role of airport management is murky at best. It's an approach that sets the United States apart from most other developed nations, where individual airports are charged with overseeing security for the entire facility and are subjected to regulation and covert testing by the government.

Boim says the latter approach might work better at big airports like LAX or O'Hare.

Other experts agree: Rafi Ron, a former director of security of Tel Aviv airport, has long argued that our security approach lacks cohesion. "It's like a person trying to defend his home by spending all his resources on the front door while leaving the back door wide open," he told us after a Congressional hearing on the subject in 2011. "Most of the TSA's effort has been directed at passengers and their bags, and little of it has been focused on securing the rest of the airport."